1. Field of the Invention
The invention relates to a toy construction system comprising two types of building elements. Building elements of the first type have a pair of opposed walls that define a space, wherein the space has, at free edges of the opposed walls, an open end and an open side, and wherein the walls have, on the sides facing the space, protruding ribs. Building elements of the second type have a coupling head that may, by a snap-fit effect with protruding ribs, be received and releasably secured in the space between the walls on a building element of the first type.
In such toy construction system, toy building elements of the one type can be structural elements, whereas building elements of the other of said types can be connectors for connecting two or more structural elements. The connectors may have relatively small dimensions whereas the structural elements have relatively large dimensions. The structural elements may be straight or arched bars of different lengths, or they may define or expand large or small surfaces that are used for imparting its structure to the construction built. Such toy construction system allows for easy and expedient building of large constructions.
2. Description of the Related Art
U.S. Pat. No. 5,061,219 teaches a toy construction system of the type described herein, where a first building element has a pair of opposed, parallel arms or walls that define a space that will, by snap-fit engagement, receive and secure a coupling head on one end of another, bar-shaped building element. In the sides that face towards the space each of the walls is provided with protruding ribs of which two ribs extend longitudinally to said arms, and a single rib extends transversally to the arms. The transversal ribs are arranged at a distance from the free ends of the arms and thereby they divide the space between said arms into an inner coupling chamber and an outer coupling chamber. Assembly and separation can only be accomplished along one definite direction whereas, in practice, assembly and separation are impossible along a direction transversally to said one direction, since the transversal ribs prevent this. This is due to the fact that, measured from the inner end portions of the arms to the transversal ribs, the lever arms are very short, and if said arms are to be able to open sufficiently for the coupling head to be able to pass the transversal ribs, i.e. from the internal coupling chamber to the external coupling chamber or vice versa, unrealistically much force is to be applied with the ensuing risk of the arms breaking.